Flexible display

ABSTRACT

A flexible display is disclosed. In one aspect, the display includes at least one first pattern including a plurality of display elements configured to display an image and extending in a first direction. The display device also includes at least one second pattern extending in a second direction and overlapping at least a portion of the first pattern. The second pattern has a curved shape in the first direction and the second direction crosses the first direction. The first and second patterns form at least one cavity region defining a space therebetween and the first and second patterns form a mesh structure.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/805,765 filed Jul. 22, 2015, which claims the benefit of KoreanPatent Application No. 10-2014-0195958, filed on Dec. 31, 2014, in theKorean Intellectual Property Office, the disclosures of which areincorporated herein in their entireties by reference.

BACKGROUND Field

The described technology generally relates to a display device.

Description of the Related Art

Display devices can be used for a variety of applications. As researchand development is being directed towards thinner profile and lighterdisplay devices, the range of possible applications increases. Inparticular, traditional display devices are being replaced with portablethin-film flat panel display devices.

With recent advancement in display-related technology, flexible displaysthat can be folded or rolled up have been developed. Furthermore,research and development on stretchable display devices that can bestretched into various shapes has been ongoing.

Thus, in order to meet users' growing demand for such display devices,display devices are being developed which are both flexible such thatthey can be folded or bent and stretchable such that they can bestretched in a specific direction.

However, the flexibility of display devices is limited since it dependson the material properties of the substrate and it is very difficult tomanufacture display devices that are both flexible and durable.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect is a display device that is both stretchable andflexible.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

Another aspect is a display device including at least one first patternunit including a plurality of display elements for displaying an image,and extending in a first direction; at least one second pattern unitextending in a second direction to overlap at least a portion of the atleast one first pattern unit, and having a curved shape in the firstdirection, wherein the second direction crosses the first direction; andat least one penetration unit for penetrating a space surrounded by theat least one first pattern unit and the at least one second patternunit, wherein the at least one first pattern unit and the at least onesecond pattern unit form a mesh structure.

The at least one first pattern unit can include a plurality of firstwires extending in the first direction, and the at least one secondpattern unit can include a plurality of second wires extending in thesecond direction to cross at least some of the plurality of first wires.

The at least one first pattern unit can include a plurality of firstsub-pattern units, the at least one second pattern unit can include aplurality of second sub-pattern units, and the at least one penetrationunit can include a plurality of sub-penetration units.

A first sub-pattern unit, a second sub-pattern unit and asub-penetration unit that are formed adjacent to one another can formone pixel.

The plurality of first sub-pattern units can include a plurality oflight-emitting regions, wherein the plurality of light-emitting regionseach emit red, green, or blue light.

The plurality of second sub-pattern units each can have a curved shapeprotruded in the first direction.

A concave groove can be formed at an edge of each of the plurality ofsecond sub-pattern units in the direction in which the plurality ofsecond sub-pattern units are protruded.

Some wires included in the plurality of second sub-pattern units amongthe plurality of second wires can have a curved shape corresponding tothe curved shapes of the plurality of second sub-pattern units.

The curved shapes of the plurality of second sub-pattern units can betightly stretched when the at least one second pattern unit isstretched.

The plurality of second sub-pattern units can be arranged to be bent inalternating directions with respect to the at least one first patternunit.

The plurality of second wires can include a plurality of wires, whereinthe plurality of wires are electrically connected to the plurality ofdisplay elements, respectively.

At least one among the plurality of first wires can be a scan line fortransmitting a scan signal to the pixel, and at least one among theplurality of second wires can be a data line for transmitting a datasignal to the pixel.

At least one among the plurality of second wires can be a drivingvoltage line for applying a driving voltage to the pixel.

The at least one first pattern unit can further include an insulatinglayer formed between the plurality of first wires and the plurality ofsecond wires.

The plurality of display elements can be arranged on the at least onefirst pattern unit to be spaced apart from each other.

The at least one first pattern unit and the at least one second patternunit each can include a base at a bottom thereof, wherein the base isformed of a flexible material.

The base can include an organic material.

The plurality of display elements can include a first electrode; asecond electrode; and an intermediate layer interposed between the firstelectrode and the second electrode, the intermediate layer including anorganic emission layer.

Another aspect is a flexible display, comprising at least one firstpattern including a plurality of display elements configured to displayan image and extending in a first direction; and at least one secondpattern extending in a second direction and overlapping at least aportion of the first pattern, wherein the second pattern has a curvedshape in the first direction and wherein the second direction crossesthe first direction, wherein the first and second patterns form at leastone cavity region defining a space therebetween, and wherein the firstand second patterns form a mesh structure.

In exemplary embodiments, the first pattern comprises a plurality offirst wires extending in the first direction and wherein the secondpattern comprises a plurality of second wires extending in the seconddirection to cross at least some of the first wires. The first patterncan comprise a plurality of first sub-patterns, the second pattern cancomprise a plurality of second sub-patterns, and the cavity region cancomprise a plurality of cavity sub-regions. Each of the firstsub-patterns can comprise a plurality of light-emitting regions, andeach of the light-emitting regions can emit red, green, or blue light.

In exemplary embodiments, each of the second sub-patterns has a curvedshape protruded in the first direction. A concave groove can be formedat an edge of each of the second sub-patterns in the first direction.Each of the second sub-patterns can comprise a plurality of wires havinga curved shape corresponding to the curved shapes of the secondsub-patterns. The second sub-patterns can be arranged to be bent inalternating directions with respect to the first pattern. The secondwires can be respectively electrically connected to the displayelements.

In exemplary embodiments, at least one of the first wires is a scan lineconfigured to apply a scan signal to the pixels and at least one of thesecond wires is a data line configured to apply a data signal to thepixels. At least one of the second wires can be a driving voltage lineconfigured to apply a driving voltage to the pixels. The first patterncan further comprise an insulating layer formed between the first wiresand the second wires. The display elements can be arranged on the firstpattern and can be spaced apart from each other. The display can furthercomprise a substrate formed of a flexible material, wherein the firstand second patterns are formed on the substrate. The substrate cancomprise an organic material.

In exemplary embodiments, each of the display elements comprises a firstelectrode; a second electrode; and an intermediate layer interposedbetween the first electrode and the second electrode, wherein theintermediate layer comprises an organic emission layer.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the exemplary embodiments,taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic plan view of a display device according to anexemplary embodiment;

FIG. 2 is an enlarged plan view of the portion indicated by ‘X’ in FIG.1;

FIG. 3 is a schematic plan view of the arrangement of wires of FIG. 2;

FIG. 4 is a schematic plan view of one of pixels of the display deviceof FIG. 1;

FIG. 5 is a cross-sectional view taken along line I-I′ of FIG. 1;

FIG. 6 is a cross-sectional view taken along line II-II′ of FIG. 1; and

FIGS. 7A and 7B are diagrams schematically illustrating the displaydevice of FIG. 1 when an external force is applied thereto.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present exemplary embodiments may have different forms and shouldnot be construed as being limited to the descriptions set forth herein.Accordingly, the exemplary embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.It would be obvious to those of ordinary skill in the art that exemplaryembodiments are to cover all modifications, equivalents, andalternatives falling within the scope of the described technology. Inthe following description, well-known functions or constructions are notdescribed in detail if it is determined that they would obscure thedescribed technology due to unnecessary detail.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various components, these componentsshould not be limited by these terms. These terms are only used todistinguish one component from another.

It will be understood that when a layer, region, or component isreferred to as being “formed on,” another layer, region, or component,it can be directly or indirectly formed on the other layer, region, orcomponent. That is, for example, intervening layers, regions, orcomponents may be present.

In the drawings, components that are substantially the same or thatcorrespond to each other will be denoted by the same reference numeraland will not be redundantly described here. The sizes of the elements inthe drawings may be exaggerated for the sake of clarity. In other words,such sizes and thicknesses of components in the drawings are notlimiting to actual implementations.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

FIG. 1 is a schematic plan view of a display device 1000 according to anexemplary embodiment. FIG. 2 is an enlarged plan view of the portionindicated by ‘X’ in FIG. 1.

Referring to FIGS. 1 and 2, the display device 1000 includes at leastone first pattern unit or first pattern 100, at least one second patternunit or second pattern 200, and at least one penetration unit or cavityregion 300.

The at least one first pattern unit 100 includes a base 30 at a bottomthereof.

The base 30 can include various materials. In detail, the base 30 may beformed of glass, a metal, or other organic materials.

Alternatively, the base 30 can be formed by patterning a flexiblematerial. For example, the base 30 can be formed of a material that canbe bent, folded, or rolled up. The flexible material may be ultra-thinglass, metal, or plastic. When the base 30 includes plastic, the base 30may be formed of, but is not limited to, a material having ductility anda high restoring force, e.g., a material such as one or more of:polyethersulphone (PES), polyethyeleneterepthalate (PET), polyethyelenennapthalate (PEN), polyimide (PI), and polycarbonate (PC). The base 30can be formed of a material containing an organic material so that itcan be flexible and strong.

The at least one first pattern unit 100 includes a plurality of displayelements 110 for displaying an image. The display elements 110 arearranged on the at least one first pattern unit 100 in a firstdirection.

The display elements 110 are arranged in a line on a surface of the base30 in the first direction. Referring to FIG. 2, although the displayelements 110 are arranged in a row in the first direction, they can bearranged in a plurality of rows. The display elements 110 can generatevisible light of various colors. In certain embodiments, the displayelements 110 include a red element Er that generates red visible light,a green element Eg that generates green visible light, and a blueelement Eb that generates blue visible light. Each of the displayelements 110 can be an organic light-emitting diode (OLED), a liquidcrystal element, or another display element. For convenience ofexplanation, it is assumed in the present disclosure that a displaydevice according to an exemplary embodiment is an OLED display includingOLEDs.

Since the OLEDs are susceptible to being damaged by the exposure to theenvironment, such as to oxygen or moisture, a protective film (notshown) can be adhered onto the base 30 to air-tightly protect the OLEDs.In some embodiments, the protective film includes a stack structure of aplurality of insulating films. In detail, organic films and inorganicfilms can be alternately stacked in the stack structure of theinsulating films.

One pixel PXL includes at least one display element as described aboveto display an image. One pixel PXL can include a plurality oflight-emitting regions. For example, one pixel PXL may include a redlight-emitting region with a red element Er, a green light-emittingregion with a green element Eg, and a blue light-emitting region with ablue element Eb. The pixel PXL having the above-described displayelements will be described with reference to FIGS. 4 to 6 below.

The at least one first pattern unit 100 includes a plurality of wires.The wires may be formed on a layer below the display elements 110 of theat least one first pattern unit 100.

The at least one first pattern unit 100 can have a flat band shape. Inthis embodiment, when the base 30 formed at the bottom of the at leastone first pattern unit 100 is formed in a band shape that is narrowerthan a flat panel, the thickness of a flexible organic material can bemore easily controlled during patterning.

As described above, the at least one first pattern unit 100 can beflexible or foldable in the first direction since the base 30 at thebottom thereof is formed of a flexible organic material and a pluralityof thin films each containing an organic film are stacked to seal thedisplay elements arranged on the at least one first pattern unit 100.Also, the at least one first pattern unit 100 can be patterned in anarrow band shape to be more easily bent or folded in the firstdirection.

The at least one second pattern unit 200 extends in a second directionto overlap at least a portion of the at least one first pattern unit100.

The at least one second pattern unit 200 includes a base 30 at a bottomthereof, similar to the at least one first pattern unit 100. Similarly,the base 30 of the at least one second pattern unit 200 can be formed bypatterning a flexible material. In this embodiment, the base 30 can beformed of the same material as the base 30 of the at least one firstpattern unit 100.

Similarly, the at least one second pattern unit 200 includes a pluralityof wires. In some regions of the at least one first pattern unit 100,wires of the at least one first pattern unit 100 and wires of the atleast one second pattern unit 200 cross so as to be electricallyconnected to each other.

As illustrated in FIGS. 1 and 2, the at least one second pattern unit200 is patterned to have a curved shape in the first direction. Thus,the at least one second pattern unit 200 is elastic in the seconddirection such that the curved shape can be repeatedly stretchable andcontractible. That is, the at least one second pattern unit 200 isstretchable in the second direction.

Each of the at least one penetration units 300 is formed to penetrate aspace surrounded by adjacent two first pattern units 100 and adjacenttwo second pattern units 200. That is, each of the at least onepenetration unit 300 is arranged between one first pattern unit 100 andanother first pattern unit 100 adjacent to the first pattern unit 100and between one second pattern unit 200 and another second pattern unit200 adjacent to the second pattern unit 200.

In the at least one penetration unit 300, the base 30 defines an openingto the environment rather than enclosing the penetration unit 300. Forexample, the at least one penetration unit 300 can be included in the atleast one first pattern unit 100 and the at least one second patternunit 200 when the at least one first pattern unit 100 and the at leastone second pattern unit 200 are manufactured. As another example, the atleast one penetration unit 300 can be formed by removing a region of thebase 30, for example, by etching. The at least one penetration unit 300can be formed in various ways and a method of manufacturing the at leastone penetration unit 300 is not limited.

By forming the at least one penetration unit 300 in a space surroundedby the at least one first pattern unit 100 and the at least one secondpattern unit 200 as described above, a plurality of first pattern units100 and a plurality of second pattern units 200 form a mesh structure.Thus, stress caused by an external stimulus such as bending, stretching,etc. can be dispersed, and the display device 1000, the shape of whichcan be changed individually in the first direction and the seconddirection can be provided.

FIG. 3 is a schematic plan view of the arrangement of the wires of FIG.2.

Referring to FIG. 3, the at least one first pattern unit 100 includes aplurality of first wires 220 extending in the first direction. The firstwires 220 can be arranged in parallel in the first direction.

The first wires 220 can include, but are not limited to, a scan line GWand a preceding scan line GI for transmitting a scan signal and apreceding scan signal to a pixel PXL and an emission control line EM fortransmitting an emission control signal to the pixel PXL.

More specifically, in the illustrated embodiment, a scan driver (notshown) transmits two corresponding scan signals to each of the pixelsPXL via the scan lines GW and GI. That is, a first scan signal can betransmitted via a scan line GW corresponding to a row including each ofthe pixels PXL in the first direction and a second scan signal can betransmitted via a preceding scan line GI to a preceding row. Also, thescan driver generates and transmits an emission control signal to eachof the pixels PXL via a plurality of emission control lines EM. However,exemplary embodiments are not limited thereto and the display device1000 can further include an emission control driver and the emissioncontrol signal can be generated by the emission control driver.

The at least one first pattern unit 100 can include not only the firstwires 220 but also wires connecting the first wires 220, second wires220, and the display elements 110.

The at least one second pattern unit 200 includes the second wires 220extending in the second direction. The second wires 220 can be arrangedin parallel in the second direction.

The second wires 220 can include data lines Data_R, Data_G, and Data_Bthat cross the scan lines GW and GI described above and via which a datasignal is transmitted to each of the pixels PXL. The second wires 220can also include a driving voltage line ELVDD via which a drivingvoltage is applied to each of the pixels PXL and that extends inparallel to the data lines Data_R, Data_G, and Data_B and a resetvoltage line Vint for applying a reset voltage for resetting a drivingthin-film transistor (TFT).

More specifically, a data driver transmits a data signal to each of thepixels PXL via the data lines Data_R, Data_G, and Data_B. Each of thepixels PXL emits light having a brightness based on the driving currentsupplied to the OLEDs according to the data signal transmitted to thepixel PXL via the data lines Data_R, Data_G, and Data_B. In theillustrated embodiment, the driving voltage line ELVDD is formed to besubstantially parallel to the data lines Data_R, Data_G, and Data_B.Since a plurality of driving voltage lines ELVDD are connected in a meshstructure by additional wires (not shown) formed in the first direction,power can be supplied via the driving voltage lines ELVDD in the firstdirection and the second direction. Thus, the additional wires forsupplying power reduce the resistance between the power supply and thepixels to prevent a voltage drop along the wires. Although the resetvoltage line Vint is illustrated as being arranged substantiallyparallel to the data lines Data_R, Data_G, and Data_B, exemplaryembodiments are not limited thereto and the reset voltage line Vint canbe formed substantially parallel to the scan lines GW and GI.

As illustrated in FIG. 3, in particular, the data lines Data_R, Data_G,and Data_B among the second wires 220 are electrically connected to thedisplay elements 110 (which are arranged on the first pattern unit 100apart from each other) to transmit a data signal. For example, the reddata line Data_R, the green data line Data_G, and the blue data lineData_B are respectively electrically connected to the red element Er,the green element Eb, and the blue element Eb. Also, driving power canbe supplied to the red element Er, the green element Eb, and the blueelement Eb via one driving voltage line ELVDD arranged in parallel tothe data lines Data_R, Data_G, and Data_B. However, the design of thesecond wires 220 including the data line Data_R, Data_G, and Data_B, andthe driving voltage line ELVDD is not limited to that described above.

As described above, the first and second wires 220 that cross in regionsof the first pattern unit 100 can be formed on different layers. Thatis, in some embodiments, the first wires 220 acting as scan wires arearranged on a lower layer and the second wires 220 acting as data wiresare arranged on an upper layer to prevent an increase in load on thewires and provide a more efficient use of space. An insulating layer(not shown) can be interposed between the first and second wires 220.

Various techniques can be used to pattern the wires 220. For example,electron beam evaporation, thermal evaporation, sputtering,electroplating, etc. can be used. In addition, the wires can be formedby performing a patterning process using photoresist and then performinga dry or wet etch process. Otherwise, the wires 220 can be directlyprinted using a printing process such as nano-imprinting or ink jetprinting. In particular, the wires 220 need to be patterned to asufficient thickness, considering that they may be stretched in thesecond direction.

The material used to form the wires 220 is not limited provided that thematerial conducts electric current and can be a metal. In thisembodiment, the metal can be at least one of the following materials:gold (Au), silver (Ag), platinum (Pt), copper (Cu), nickel (Ni),chromium (Cr), aluminum (Al), tungsten (W), titanium (Ti), and palladium(Pd). The material of the wires 220 can be appropriately selected basedon electrical and mechanical properties such as conductivity, ductility,malleability, etc.

FIG. 4 is a schematic plan view of one of pixels of the display device1000 of FIG. 1.

Referring to FIG. 4, a first pattern unit 100 includes a plurality offirst sub-patterns unit or first sub-patterns 100′, a second patternunit 200 includes a plurality of second sub-pattern units or secondsub-patterns 200′, and a penetration unit 300 includes a plurality ofsub-penetration units or cavity sub-regions 300′.

In this embodiment, one pixel PXL is formed by two adjacent firstsub-pattern units 100′, two adjacent second sub-pattern units 200′ and asub-penetration unit 300′ interposed therebetween. When the length ofone pixel PXL in the first direction is ‘A’, the length A is determinedto be an appropriate value according to the resolution of the displaydevice 1000.

As described above, one pixel PXL includes a plurality of light-emittingregions. For example, each of the light-emitting regions can emit red,green, or blue light. Also, in each of the light-emitting regions, a redelement Er that generates red visible light, a green element Eb thatgenerates green visible light, and a blue element Eb that generates bluevisible light can be arranged. The light-emitting regions are formed inthe first sub-pattern units 100′. When the width of a first sub-patternunit 100′ in the second direction is ‘B’, the width B can be determinedaccording to the positions of a pixel circuit connected to each oflight-emitting devices and the first wires 220, and is influenced by alight emission aperture ratio of each of the light-emitting regions.

The second sub-pattern units 200′ have a curved shape in the firstdirection. The second sub-pattern units 200′ can have various shapesaccording to a degree of strain applied thereto and the material of thesubstrate. The shapes of the second sub-pattern units 200′ are notlimited, provided that stress applied to the display device 1000 can bedispersed by the second sub-pattern units 200′. For example, the secondsub-pattern units 200′ can have a hemisphere shape or a screw shape.Also, some second wires 220 formed on the second sub-pattern unit 200′are formed in a curved shape corresponding to the shapes of the secondsub-pattern unit 200′.

In the embodiment of FIG. 4, when the width of a portion of the secondsub-pattern units 200′, which is curved to a great extent in the firstdirection, is ‘C’, the width C is influenced by the material andfeatures of the insulating films and is determined to be an appropriatevalue according to the number and position of the second wires 220.

Also, a concave groove is formed at an edge of each of the secondsub-pattern units 200′ in a direction in which the second sub-patternunits 200′ are curved. When the width of the concave groove in thesecond direction is ‘D’, the stretchability of the second pattern unit200 in the second direction is determined by the width D and amechanical strength of the second sub-pattern unit 200′ is influenced bythe width D.

As described above, the second pattern unit 200 can act as a spring byforming a groove in the second sub-pattern unit 200′. That is, thecurved shape of the second sub-pattern unit 200′ is tightly stretchedwhen the second pattern unit 200 is stretched in the second direction.Furthermore, portions of the second wires 220 arranged on the secondsub-pattern unit 200′ to correspond to the shape of the secondsub-pattern unit 200′ are also tightly stretched in the seconddirection.

The second sub-pattern units 200′ and the second wires 220 arranged onthe second sub-pattern units 200′ can be formed to be bent inalternating directions with respect to the first pattern unit 100. Thus,wire resistances of the red element Er, the green element Eb, and theblue element Eb with respect to the first pattern unit 100 in the firstdirection are equalized to more stably drive the display device 1000.However, the pattern of the second sub-pattern units 200′ and the secondwires 220 is not limited to the embodiment illustrated in FIG. 2 or 3.For example, two second sub-pattern units 200′ can be arranged betweentwo adjacent first pattern units 100 in alternating orientations to forman ‘S’ shape. As another example, second sub-pattern units 200′ curvedin the same direction can be arranged in a plurality of rows and secondsub-pattern units 200′ curved in a different direction can be arrangedin a plurality of rows adjacent to the plurality of rows, therebybalancing wire resistances.

A stack structure of first pattern units 100 and second pattern units200 in a direction of the thickness thereof will be described below.

FIG. 5 is a cross-sectional view taken along line I-I′ of FIG. 1. FIG. 6is a cross-sectional view taken along line II-II′ of FIG. 1.

First, a cross-sectional view of the first pattern unit 100 includingone OLED will be described with reference to FIG. 5. Here, forconvenience of explanation, a region of a base or substrate 30 in whichone OLED is included as a display element will be referred to as adisplay unit P.

The base 30 can be formed of a flexible material. For example, the base30 can be formed of a plastic material. The plastic material can be anelectrically insulating organic material such as one or more of:polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI),polyethyelene napthalate (PEN), polyethyelene terepthalate (PET),polyphenylene sulfide (PPS), polyallylate, polyimide (PI), polycarbonate(PC), triacetyl cellulose (TAC), and cellulose acetate propionate (CAP).

When the display device is a bottom emission type display in which animage can be viewed via the base 30, the base 30 should be formed of atransparent material. However, when the display device is a top emissiontype display in which an image can be view from a direction opposite tothe base 30, the base 30 need not be formed of a transparent material.

Although the base 30 can be formed of a plastic material, an ultra-thinglass or a metal material can be used, provided that it has anelectrically insulating property. When the base 30 is formed of a metal,the base 30 can include, but is not limited to, at least one of thefollowing materials: carbon, iron, chromium, manganese, nickel,molybdenum, stainless steel (SUS), an Invar alloy, an Inconel alloy, anda Kovar alloy.

The display unit P can be formed on the base 30 and include a TFT T1 andan OLED.

Referring to FIG. 5, a buffer layer 31 can be formed on the base 30. Thebuffer layer 31 is a layer that protects the base 30 against impuritiesand provides a flat surface on the base 30. The buffer layer 31 can beformed of various materials that can provide the above functions of thebuffer layer 31. For example, the buffer layer 31 can include aninorganic material such as silicon oxide (SiO_(x)), silicon nitride(SiN_(x)), silicon oxynitride (SiO_(x)N_(y)), aluminum oxide, aluminumnitride, titanium oxide, or titanium nitride; an organic material suchas polyimide (PI), polyester, or acrylic, or may be a multi-layer filmincluding at least one among these materials.

An active layer 107 is formed on the buffer layer 31 by using aninorganic semiconductor such as silicon or an organic semiconductor. Theactive layer 107 includes a source region, a drain region, and a channelregion between the source region and the drain region. For example, whenthe active layer 107 is formed of amorphous silicon, the active layer107 including the source region, the drain region, and the channelregion between the source region and the drain region can be formed byforming an amorphous silicon layer on the entire base 30, crystallizingthe amorphous silicon layer to form a polycrystalline silicon layer,patterning the polycrystalline silicon layer, and doping impurities intoa source region and a drain region at edges of the resultant structure.

A gate insulating film 32 is formed on the active layer 107. The gateinsulating film 32 electrically insulates the active layer 107 and agate electrode 108 from each other and can be formed of an inorganicmaterial such as silicon nitride (SiN_(x)), silicon oxide (SiO₂), etc.

The gate electrode 108 is formed in a predetermined upper region of thegate insulating film 32. The gate electrode 108 is connected to a gateline (not shown) for supplying an ‘on’/‘off’ signal to the TFT T1. Here,a plurality of gate electrodes 108 can be formed and the gate insulatingfilm 32 can be additionally interposed between the gate electrodes 108.

The gate electrode 108 can include Au, Ag, Cu, Ni, Pt, Pd, Al, ormolybdenum (Mo) or an alloy such as an Al:Nd alloy or a Mo:W ally but isnot limited thereto and may be formed of various materials inconsideration of design conditions.

An interlayer insulating film 33 formed on the gate electrode 108insulates a source electrode 109 a and a drain electrode 109 b and canbe formed of an inorganic material such as SiN_(x), SiO₂, etc.

The source electrode 109 a and the drain electrode 109 b are formed onthe interlayer insulating film 33. In detail, the interlayer insulatingfilm 33 and the gate insulating film 32 are formed to expose the sourceregion and the drain region of the active layer 107. The sourceelectrode 109 a and the drain electrode 109 b are formed to be incontact with the exposed source region and drain region of the activelayer 107.

Although FIG. 5 illustrates a top gate type TFT in which the activelayer 107, the gate electrode 108, the source electrode 109 a, and thedrain electrode 109 b are sequentially formed, exemplary embodiments arenot limited thereto and the gate electrode 108 can be formed below theactive layer 107. More specifically, the TFT T1 can have alow-temperature polycrystaline silicon (LTPS) top gate structure, anoxide bottom gate structure, or an oxide top gate structure.

An insulating film stack structure 34 is formed on a region of the base30 except for the TFT T1 by sequentially forming the buffer layer 31,the gate insulating film 32, and the interlayer insulating film 33.

The TFT T1 is electrically connected to the OLED so as to drive the OLEDand is protected by being covered with a planarizing film 35.

The planarizing film 35 can include an inorganic insulating film and/oran organic insulating film. The inorganic insulating film may includeone or more of: SiO₂, SiN_(x), SiON, Al₂O₃, TiO₂, Ta₂O₅, HfO₂, ZrO₂,BST, PZT, etc. The organic insulating film may include a general-purposepolymer (PMMA or PS), a polymeric derivative having a phenol-basedgroup, an acryl-based polymer, an imide-based polymer, anarylether-based polymer, an amide-based polymer, a fluorine-basedpolymer, a p-xylene-based polymer, a vinyl alcohol-based polymer, amixture thereof, etc. Also, the planarizing film 35 can be a compositestack structure of an inorganic insulating film and an organicinsulating film.

The OLED can include a first electrode 111, an intermediate layer 112,and a second electrode 113.

The first electrode 111 is formed on the planarizing film 35 and iselectrically connected to the drain electrode 109 b via a contact hole105 formed in the planarizing film 35.

The first electrode 111 can be a reflective electrode and include areflective film formed of Ag, magnesium (Mg), Al, Pt, Pd, Au, Ni,neodymium (Nd), iridium (Ir), Cr, or a mixture thereof and a transparentor semi-transparent electrode layer formed on the reflective film. Thetransparent or semi-transparent electrode layer may include at least oneof the following materials: indium tin oxide (ITO), indium zinc oxide(IZO), zinc oxide (ZnO), indium oxide (In₂O₃), indium gallium oxide(IGO), and aluminum zinc oxide (AZO).

The second electrode 113 is formed opposite to the first electrode Illand can be a transparent or semi-transparent electrode. The secondelectrode 113 can be formed of a metal thin film having a low workfunction and including Li, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, or a mixturethereof. Also, an auxiliary electrode layer or a bus electrode can befurther formed on the metal thin film by using a transparent electrodeforming material such as ITO, IZO, ZnO, In₂O₃, etc.

Thus, the second electrode 113 can allow light emitted from an organicemission layer (not shown) included in the intermediate layer 112 topass therethrough. That is, the light emitted from the organic emissionlayer can be emitted directly toward the second electrode 113 or can bereflected from the first electrode 111 configured as a reflectiveelectrode and emitted toward the second electrode 113.

However, the display device according to the present embodiment is notlimited to a top emission type and can be a bottom emission type inwhich light emitted from the organic emission layer is discharged towardthe base 30. In this embodiment, the first electrode 111 can be atransparent or semi-transparent electrode and the second electrode 113can be a reflective electrode. Otherwise, the display device 1000according to the present embodiment can be a dual emission type in whichlight is emitted in both a forward direction and a backward direction.

A pixel defining layer 36 is formed on the first electrode 111 by usingan electrically insulating material. The pixel defining layer 36 can beformed by spin coating and using at least one of the following organicinsulating materials: polyimide (PI), polyamide, acrylic resin,benzocyclobutene (BCB) and phenol resin. The pixel defining layer 36exposes a predetermined region of the first electrode 111 and theintermediate layer 112 including the organic emission layer is formed onthe exposed region of the first electrode 111.

The organic emission layer included in the intermediate layer 112 can bea low molecular weight organic material or a high molecular weightorganic material. In addition to the organic emission layer, theintermediate layer 112 can selectively further include a functionallayer such as a hole transport layer (HTL), a hole injection layer(HIL), an electron transport layer (ETL), an electron injection layer(EIL), etc.

Although not shown, an encapsulation layer (not shown) can be formed onthe second electrode 113. The encapsulation layer can have a structurein which a plurality of inorganic films are stacked or an organic filmand an inorganic film are alternately stacked. As another example, anencapsulation substrate (not shown) can be formed on the secondelectrode 113 so that the display device 1000 can be sealed with theencapsulation substrate.

Also, in order to protect the second electrode 113, a capping layer (notshown) can be interposed between the encapsulation layer/encapsulationsubstrate and the second electrode 113.

Next, a cross-sectional view of a second sub-pattern unit 200′ will bedescribed with reference to FIG. 6. In FIG. 6, components that are thesame as those in FIG. 5 are denoted by the same reference numeralscomponents and are not redundantly described here.

A base 30 can be formed of a flexible material similar to a firstpattern unit 100. An insulating film stack structure 34 is formed on thebase 30 by sequentially forming a buffer layer 31, a gate insulatingfilm 32, and an interlayer insulating film 33.

A wire layer 109 is formed on the insulating film stack structure 34.The wire layer 109 can be formed of the same material as the sourceelectrode 109 a and the drain electrode 109 b of FIG. 5. The wire layer109 corresponds to the second wires 220 of FIGS. 2 and 3.

A planarizing film 35 is formed on the insulating film stack structure34 to cover the wire layer 109. A second electrode 113 is formed on theplanarizing film 35. The second electrode 113 is formed to cover theentire display device 1000 including the first pattern unit 100 of FIG.5.

As described above, the display devices 1000 according to the one ormore of the above embodiments can be embodied as having differentfunctions in the first direction and the second direction.

FIGS. 7A and 7B are diagrams schematically illustrating the displaydevice 1000 of FIG. 1 when an external force is applied thereto.

Referring to FIG. 7A, the first pattern unit 100 is patterned in anarrow band shape in the first direction, so that the display device1000 can be more easily bent or folded in the first direction. Thus, thedisplay device 1000 can be flexible or foldable in the first direction.

Referring to FIG. 7B, the second pattern unit 200 is patterned in acurved shape in the second direction, so that the curved shape can berepeatedly stretched and contracted. That is, the curved shape can actas an elastic body and apply an elastic force to the display device1000. Thus, the display device 1000 can be stretchable in the seconddirection.

As described above, display devices according to exemplary embodimentscan be both stretchable and flexible.

Also, display devices according to exemplary embodiments can improve theuser experience.

It should be understood that the exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exemplaryembodiment should typically be considered as available for other similarfeatures or aspects in other exemplary embodiments.

While one or more exemplary embodiments have been described withreference to the figures, it will be understood by those of ordinaryskill in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the following claims.

What is claimed is:
 1. A flexible display device, comprising: asubstrate including an opening; a plurality of display elements disposedon the substrate and extending in a first direction; and a plurality offirst wires extending in the first direction, the plurality of firstwires are respectively electrically connected to the display elements,and a plurality of second wires disposed on the substrate, having acurved shape, and extending in a second direction cross to the firstdirection, wherein the opening is surrounded by the plurality of displayelements and the plurality of second wires.
 2. The flexible displaydevice of claim 1, wherein the curved shape includes a first curvedportion and a second curved portion, wherein an open end of the firstcurved portion faces a direction different from an open end of thesecond curved portion.
 3. The flexible display device of claim 1,wherein a portion of the opening has a shape corresponding to the curvedshape.
 4. The flexible display device of claim 1, wherein the openingincludes a plurality of sub openings, each of the plurality of subopenings is surrounded by the plurality of display elements and theplurality of second wires.
 5. The flexible display device of claim 1,wherein at least one of the second wires is a driving voltage lineconfigured to apply a driving voltage to the at least one of the displayelements.
 6. The flexible display device of claim 1, further comprisinga plurality of first wires extending in the first direction, and theplurality of first wires includes wires spaced apart from each otheraround the opening.
 7. The flexible display device of claim 1, furthercomprising an insulating layer disposed between the plurality of firstwires and plurality of the second wires.
 8. The flexible display deviceof claim 1, wherein the plurality of second wires includes a firstsub-wire and the second sub-wire spaced apart from each other around theopening, and at least two display elements emitting different colors arearranged between the first sub-wire and the second sub-wire.
 9. Theflexible display device of claim 1, wherein the substrate includes anorganic material.
 10. The flexible display device of claim 1, whereineach of the plurality of the display elements comprises: a firstelectrode; a second electrode; and an intermediate layer interposedbetween the first electrode and the second electrode, wherein theintermediate layer comprises an organic emission layer.